Given everything else I reluctant to play Devil's Advocate, but... at the time of this incident, Sky was a newborn. Sleep deprivation and the massive changes to their routine likely played a huge part. I've known more than one caring parent who, in the early days, would get ready to go somewhere and forget to include the newborn (hey, at least they remembered before leaving the house), and a few who wrangled the kids out, got halfway across the parking lot and realised they were a kid short. My own father did it once- we got most of the way through a meal at McDonald's when he remembered that Sister wasn't home with my mother like she usually was. It is surprisingly common (not in an "every parent does it" way, but you probably know somebody it nearly happened to), but nobody wants to talk about it. Which is a shame, because I think honesty will breed awareness and reduce incidents, but that's a whole other topic. Now, given mom apparently did it a second time(which I don't but, but whatever), that's just a whole other bag of a WTFery.